<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css" media="screen">
		*{
			padding: 0;
			margin: 0;
		}
		#fk{
			width: 1200px;
			height: 1000px;
			border: 2px solid orangered;
			margin: 20px auto;
			display: flex;
			flex-wrap: wrap;
			/* 多跟轴线对齐方式flex-start flex-end center  spance-between space-around*/
			align-content: center;
			
		}
		#fk div{
			width: 200px;
			height: 200px;
			background: dodgerblue;
			font-size: 40px;
			text-align: center;
			color: white;
			border: 1px solid green;
			flex: 1;
		}
		#fk>div:nth-child(3){
			flex: 2;
		}
	</style>
</head>
<body>
	<div id="fk">
		<div>1</div>
		<div>2</div>
		<div>3</div>
		<div>4</div>
		<div>5</div>
		<div>6</div>
		<div>7</div>
		<div>8</div>
		<div>9</div>
		<div>4</div>
		<div>5</div>
		<div>6</div>
		<div>7</div>
		<div>8</div>
		<div>9</div>
	</div>
</body>
</html> 